1. Field of the Invention
The present invention relates to an information recording medium and, more particularly, to an optical disk memory such as a compact disk (CD), a magneto-optical disk (MO), and the like, from which information can be read out using light.
2. Related Background Art
An optical disk having amplitude-modulated marks is called a phase change type disk (PC disk). Such an optical disk has been practically applied to video image files, document files for business use, and as an external memory for a personal computer. Such an information recording medium is described in U.S. Pat. No. 4,423,502.